package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.boot.autoconfigure.cache.CacheProperties;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;


    @Override
    public Result queryById(Long id) {
        //缓存穿透
        //Shop shop = queryWithPassTrough(id);
        //Shop shop = cacheClient.queryWithPassTrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //利用互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //逻辑过期解决缓存击穿
        //Shop shop = queryWithLogicalExpire(id);
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);



        if (shop == null){
            return Result.fail("店铺不存在");
        }

        return Result.ok(shop);

    }

    //缓存穿透
    /*public Shop queryWithPassTrough(Long id){
        //1.从redis查询商铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3.存在 直接返回数据
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //判断命中的是否是空值
        if (shopJson != null) {
            //返回一个错误信息
            return null;
        }

        //4.不存在，根据id查询数据库
        Shop shop = getById(id);
        //5.判断数据库是否存在该id的商铺
        if (shop == null) {
            //将空值写入redis
            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
            //6.不存在，返回错误
            return null;
        }
        //7.存在 写入redis
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //8.返回
        return shop;
    }*/

    //缓存击穿之互斥锁
    /*
    public Shop queryWithMutex(Long id){
        //1.从redis查询商铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3.存在 直接返回数据
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //判断命中的是否是空值
        if (shopJson != null) {
            //返回一个错误信息
            return null;
        }


        //4.实现缓存重建
        //4.1获取互斥锁
        String lockKey = "lock:shop:" + id;
        Shop shop = null;

        try {
            Boolean isLock = tryLock(lockKey);
            //4.2 判断是否获取锁成功
            if(!isLock){
                //4.3 失败，则休眠一会再尝试
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //4.4 成功，根据id查询数据库
            shop = getById(id);

            //5.判断数据库是否存在该id的商铺
            if (shop == null) {
                //将空值写入redis
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
                //6.不存在，返回错误
                return null;
            }
            //7.存在 写入redis
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        }catch (Exception e ){
            throw new RuntimeException(e);
        }finally {
            //8. 释放互斥锁
            unLock(lockKey);
        }
        //9. 返回
        return shop;
    }
*/

    //缓存击穿之逻辑过期
    /*public Shop queryWithLogicalExpire(Long id){
        //1.从redis查询商铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isBlank(shopJson)) {
            //3.不存在
            return null;
        }
        //4.命中，需要先把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        //5.判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())){
            //5.1 未过期，直接返回店铺信息
            return shop;
        }
        //5.2 已过期，需要缓存重建

        //6.缓存重建
        //6.1 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        Boolean isLock = tryLock(lockKey);
        //6.2判断是否获取锁成功
        if (isLock) {
            //6.3成功，开启独立线程
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    //重建缓存
                    this.saveShop2Redis(id,20L);
                }catch (Exception e){
                    throw new RuntimeException(e);
                }finally {
                    //释放锁
                    unLock(lockKey);
                }
            });
        }
        //6.4返回过期的商铺信息
        return shop;
    }*/

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不能为空");
        }
        //1.删除数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);

        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        /*//1.判断是否需要根据坐标查询
        if (x == null || y == null){
            //坐标为空 按数据库查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        //3.查询redis 按照距离排序，分页。结果：shopId，distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeCoordinates().limit(end)
                );
        //4.解析出id
        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        //4.1截取from~end
        ArrayList<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //4.2 获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3 获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("order by field(id," + idStr + ")").list();
        for (Shop shop : shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shops);*/
        // 判断是否需要根据坐标查询
        if(x == null || y == null){
            // 根据类型分页查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        // 计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        // 查询 Redis，按照距离排序、分页。
        GeoResults<RedisGeoCommands.GeoLocation<String>> search = stringRedisTemplate.opsForGeo().
                search(RedisConstants.SHOP_GEO_KEY + typeId,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end));

        if(search == null){
            return Result.ok(Collections.emptyList());
        }

        // 查询 Redis，按照距离排序、分页
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = search.getContent();
        if(from >= content.size()){
            return Result.ok(Collections.emptyList());
        }

        List<Long> ids = new ArrayList<>(content.size());
        Map<String, Distance> distanceMap = new HashMap<>(content.size());
        // 截取 from ~ end 的部分
        content.stream().skip(from).forEach(result -> {
            // 获取店铺 id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        String join = StrUtil.join(",", ids);
        // 根据 id 查询 shop
        List<Shop> shopList = query().in("id", ids).last("order by field(" + join + ")").list();

        for (Shop shop : shopList) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }

        return Result.ok(shopList);

    }
}
